Cohen's kappa (2 raters) API

Computes Cohen's kappa inter-rater agreement from a square confusion matrix (rater A rows x rater B columns), correcting observed agreement for chance, with a Landis-Koch interpretation. Answers 'How much do two raters agree beyond chance?', 'What is kappa for this confusion matrix?'.

Price$0.04per request

MethodPOST

Route/v1/stats/cohens-kappa

StatusLive

MIME typeapplication/json

Rate limit120/minute

Cache0s public

psychometricscohens-kappainter-rateragreementreliabilityraterskappaannotation

API URLhttps://x402.hexl.dev/v1/stats/cohens-kappa

Integration docs

Example request

{
  "matrix": [
    [
      20,
      5
    ],
    [
      10,
      15
    ]
  ]
}

Example response

{
  "kappa": 0.4,
  "observedAgreement": 0.7,
  "expectedAgreement": 0.5,
  "nSubjects": 50,
  "nCategories": 2,
  "interpretation": "fair agreement"
}

Input schema

{
  "type": "object",
  "required": [
    "matrix"
  ],
  "properties": {
    "matrix": {
      "type": "array",
      "items": {
        "type": "array",
        "items": {
          "type": "number"
        }
      },
      "description": "square confusion matrix of joint counts",
      "examples": [
        [
          [
            20,
            5
          ],
          [
            10,
            15
          ]
        ]
      ]
    }
  }
}

Output schema

{
  "type": "object",
  "additionalProperties": true
}